Apparatus for the control of highway crossing signals



Sept. 3, 1940. c. w. BELL 2,213,377

APPARATUS FOR THE CONTROL OF HIGHWAY CROSSING SIGNALS Filed Jan. 51,1939 INVENTOR Chanles W Z3611- HIS ATTORNEY Patented Sept. 3, 1940UNITED STATES PATENT APPARATUS FOR THE CONTROL OF HIGH- WAY CROSSINGSIGNALS Charles W. Bell, Forest Hills, Pa, assignor to The Union Switch& Signal Company, Swissvale, Pa, a corporation of Pennsylvania,

Application January 31, 1939, Serial No.- 253,831

4 Claims. (01. 246-130) My invention relates to apparatus for the con-WI and a second winding W2, and may take any trol of highway crossingsignals, and has for an one of the well-known forms of interlockingobject the provision of novel and improved means relays characterized bythe fact that the first to provide directional control of ahighwaycrosswinding only of the two windings to be suc- 5 ing signal for atrack over which trains move cessively deenergized is permitted to openor close 5 in each direction, where conditions are such that its frontor back control contacts, the second the control track sections for thesignal cannot winding of the interlocking relay to be sucextend throughthe highway but are separated cessively deenergized being released to aninterfrom each other at the crossing by a section of locked positionwherein its front and back contrack longer than a single car or lightengine. trol contacts are latched up and are held re 10' Other objectsand advantages of my invention spectively closed or open. will appear asthe specification progresses. The immediate operating circuit for signalS I shall describe one form of apparatus empasses from one terminal B ofa suitable source bodying my invention, and shall then point out ofcurrent, such as a battery not shown, through the novel features thereofin claims. back contact l of winding Wl or back contact 5 15 Theaccompanying drawing is a diagrammatic of winding W2, and the winding ofsignal S to view of a preferred form of apparatus embodythe otherterminal C of the source of current. ing my invention. The referencecharacter TER designates a time Referring to the drawing, the referencecharelement device for at times controlling winding 20. acters l and la.designate the track rails of a W! or W2 of relay 2%. The device TEE. may

stretch of railway track over which traffic moves take any one of manyforms well known to the in both directions, and which is intersected atart, and as here shown is a thermal relay prograde by a highway I-I.Located adjacent the vided with a normally open contact 6, whichintersection is a highway crossing signal, desigcontact is closed in apredetermined time inter- 25 nated by the reference character S. SignalS val after relay TEE is energized. Relay HER 80 may take any one ofseveral forms, and as here is provided with three energizing circuits, afirst shown is an audible signal in the form of an circuit of whichpasses from terminal B through electric bell. back contact l of windingW l or back contact 8 The track rails I and la are divided by means ofwinding W2, front contact 9 of relay 2TB,

of the usual insulated track joints 2 into the front contact iii ofrelay lTR, and the winding 3'5 track sections D-E and FG, which sectionsof relay TER to terminal 0; a second path of extend in oppositedirections from the interwhich passes from terminal B through backconsection. The sections D-E and FG are protact ll of winding Wl, backcontact 52 of relay vided with track circuits comprising in each in-2TB, front contact l3 of relay iTR, and the stance a suitable source ofcurrent, such as winding of relay TER to terminal C; and a third trackbattery 3, connected across the rails at path of which passes fromterminal B through one end of the section, and a track relay, desigbackcontact it of winding W2, front contact is hated by the referencecharacter lTR or 2TB, of relay 2TB, back contact to of relay lTR, andconnected across the track rails at the other end. th winding of relayTER to terminal (3.

40 The section EF, which iS intermediate the The apparatus embodying myinvention is in Sections and and Which contailfls h its normal conditionwhen no trains are operathighwa'y is not provided Wlth track clrcult ingon the track rails l and la intermediate the it being assumed that atthe points D and Gr. In this normal condition of n 1terect1n render.esmbhfshment. of aitrmk the apparatus, as shown in the drawing, relayscircuit for that section impossible or inadvisable. 6TB, 2TH andwindings W5 and W2 of KR are The section EFI shall assume to be longerthan d and Tel m1 Si 1 a d the length of a single car or light engineoperatg l c l D ing on the tracks l and lot, while the sectionsenvrglzed Wmdmg 9 energized over a stick circuit which may be D--E andFG I shall assume to be sufiiciently 1 50 long enough to provide anadequate Warning traced from terminal B through front contact i'i periodto highway users f the approach of a of winding Wi, front contact iii ofrelay lTR and train t t intersection, the winding Wi of relay XR. toterminal C.

The reference character XR designates an Winding W2 is normallyenergized over a stick interlocking relay for controlling the operationcircuit which may be traced from terminal B of signal S. Relay XRcomprises a first winding through front contact it of winding W2, frontcontact 20 of relay 2TB, and winding W2 of relay XR to terminal C.

In describing the operation of the apparatus embodying my invention, Ishall assume that an eastbound train, that is, a train operating fromleft to right in the drawing, enters section DE so that relay ITR isshunted and releases. When this happens, front contact I8 of relay ITRis opened to open the stick circuit just traced for winding WI, with theresult that winding WI releases to close its back contact 4 and therebycomplete the operating circuit for signal S, 50 that signal S becomesenergized to display its warning indication to highway users of theapproach of the train to the intersection. Front contact II of windingWI is also opened when winding W I releases, so that the stick circuitfor winding WI is opened at that point. Back contacts I and II ofwinding WI are also closed, to prepare respectively the first and secondenergizing circuits for relay TER.

In the event that the train is long enough to bridge both sections DEand F-G, the entrance of the train on section F-G and consequentshunting of relay 2TB results in relay 2TB releasing. When this happens,front contact 2!) of relay 2TB is opened to open the stick circuitpreviously traced for winding W2 with the result that winding W2 isdeenergized and releases its armature to its interlocked position,wherein front contact I9 of winding W2 remains closed and back contacts5, 8 and IA of winding W2 are prevented from closing.

When the train vacates section DE, relay ITR picks up to close its frontcontacts I8 and I3, the closing of front contact I8 of relay ITRpreparing the stick circuit for winding WI, while the closing of frontcontact I3 completes the second energizing circuit for relay TER, whichcircuit, as pointed out hereinbefore, includes back contact II ofwinding WI, back contact I2 of relay 2TB, and front contact I3 of relayITR. Relay 'I'ER at the end of its predetermined time interval ofenergization closes contact 6 to establish a pick-up circuit for windingWI, which circuit may be traced from terminal B through front contact I9of winding W2, contact 6 of relay TER, front contact I8 of relay ITR,and the winding W! of relay XR to terminal C. Winding WI picks up overits pick-up circuit to open back contacts 4 and II, the opening of backcontact 4 interrupting the operating circuit for signal S, and theopening of back contact II opening the second energizing circuit forrelay TER. The picking up of winding WI of relay XR also closes frontcontact I! to complete its previously traced stick circuit, with theresult that winding WI is held energized over that circuit when contact6 of relay 'IER is opened upon the deenergization of that relay. It isto be noted that since winding W2 is released to its interlockedposition prior to winding WI picking up, directional control of thesignal S is established whereby the operation of the signal is noteifected by a train operating through a control section in receding fromthe intersection.

When the train vacates section FG, relay 2TB, picks up to close frontcontact 28 and thereby complete the stick circuit for winding W2, withthe result that Winding W2 picks up so that the apparatus is restored toits normal condition.

In the event that the eastbound train operating over tracks I and Ia isshort so that it does not bridge sections D-E and F-G, then the trainwill vacate section DE and relay ITR will pick up, prior to the trainentering section F-G. When the train vacates section DE and relay ITRpicks up, the first energizing circuit for relay TER is completed, whichcircuit includes back contact I of winding WI, front contact 9 of relay2TB and front contact II] of relay ITR, Relay TER becomes energized, butsince relay TER does not close its contact 6 until the expiration of itspredetermined time interval, the train will ordinarily enter section F-Gto efiect the deenergization of relay 2TB and of winding W2 to itsinterlocked position, prior to contact 6 of relay TER closing.

The release of relay 2TB, when the train enters section F--G, and theconsequent release of winding W2 of relay XR to its interlockedposition, results in the opening of the first energizing circuit forrelay TER, but relay TER is held energized over its previously tracedsecond energizing circuit. The operation of the apparatus with the shorttrain on section F-G is now substantially similar to the operation forthe long train on section F-G. That is to say, relay TER. is energizedand closes its contact 6 at the expiration of its predetermined timeinterval, whereupon winding WI picks up to complete its own stickcircuit, which holds winding WI energized when relay TER opens itscontact 6. When section F-G is vacated, relay 2TB, and winding W2 pickup to restore the apparatus to the normal position.

The operation of the apparatus embodying my invention for both a longand short westbound train is substantially similar to the operation justdescribed for a long and a short eastbound train, and it is thought thatthis latter operation for the Westbound train will be readily apparentfrom the foregoing description for the operation of the eastbound traintogether with an inspection of the drawing without further detailedexplanation.

It is to be noted that relay TER functions to restore winding WI or W2to its normal condition when a train enters the control section toinitiate the operation of signal S, but which train reverses itsdirection and vacates that section without proceeding across theintersection. That is to say, since relay TER is energized over itsfirst energizing circuit when winding WI or W2 is released and bothtrack relays I'I'It and 2TH are picked up, it follows that when aneastbound train, for example, reverses direction in section DE andvacates that section after having initiated the operation of signal S,then relay 'IER is energized and completes at the end of itspredetermined time interval the pick-up circuit for winding WI whereuponwinding WI is restored to its normal condition and the operation ofsignal S is terminated.

It should further be noted that although the control track sectionscannot be extended to the intersection, the intersection is protectedfor a predetermined time interval after the train vacates the controlsection on the approach side of the intersection, and that directionalcontrol of the signal is established.

Although I have herein shown and described only one form of apparatusembodying my invention, it is understood that various changes andmodifications may be made therein within the scope of the appendedclaims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. In combination, a stretch of railway track divided into a firstsection and a second section separated from each other by anintermediate section, a signal, a first relay operable by a car enteringsaid first section, a second relay operable by a car entering saidsecond section, operating means controlled by each of said first andsecond relays for operating said signal for railway traffic approachingthe intermediate section in either of said first and second sections, atiming device effective when operated to control said operating means toterminate operation of said signal, and circuit means controlled by saidoperating means and including a back contact of the track relayassociated with the section on the receding side of the intermediatesection for operating said time element device whenever the section inapproach of the intersection is vacated provided the other section isoccupied, the characteristics of said timing device being such as tomaintain operation of said signal by said operating means during thetime interval required for a car to traverse said intermediate section.

2. In combination, a stretch of railway track divided into two outersections separated from each other by an intermediate sectionintersected by a highway, a highway crossing signal positioned at suchintersection, a first track relay for said first section, a second trackrelay for said second section, operating means governed by said trackrelays for operating the signal when a train approaches theintersection, a time element device having a contact closed at theexpiration of a predetermined time interval after energization thereof,circuit means for energizing said time element device governed by saidtrack relays and by said operating means and effective when both saidfirst and said second sections are unoccupied, other circuit means forenergizing said time element device governed by said operating means andincluding a front contact of the track relay associated with the sectionon the approach side of the intersection and a back contact of the trackrelay associated with the section on the receding side of theintersection, and means controlled by said contact of said time elementdevice for terminating operation of said signal by said operating meanswhereby to insure the operation of said signal for said predeterminedtime interval after said approach section is vacated, said predeterminedtime interval being selected to provide operation of said signal for thetime interval required by a car moving at a normal rate of speed totraverse said intermediate section.

3. In combination, a stretch ofrailway track divided into two outersections separated from each other by an intermediate sectionintersected by a highway, a highway crossing signal positioned at suchintersection, two track relays one for each of said two outer sections,an interlocking relay having two windings one for each of said two trackrelays, operating circuit means for operating said signal governed byeach of the two windings of said interlocking relay, stick circuit meansfor normally energizing each winding of said interlocking relay governedby its associated track relay, a time element device having a contactclosed in a predetermined period contacts of said two track relaysarranged in such manner that said timing device is energized whenevereither section on the approach side of the intersection is vacatedregardless of traffic conditions in the other section on the recedingside of the intersection, whereby energization of the winding of saidinterlocking relay associated with the track relay of said approachsection is avoided'for said predetermined time interval to insureoperation of said signal for the time interval required by a car movingat a normal rate of speed to traverse said intermediate section.

4. In combination, a stretch of railway track divided into two outersections separated from each other by an intermediate sectionintersected by a highway, a highway crossing signal located at suchintersection, two track relays one for each of said two outer sections,an interlockingv relay having two windings one for each of said twotrack relays, a stick circuit controlled by each track relay fornormally energizing the associated winding of said interlocking relay,means controlled by each of said two windings of the interlocking relayfor operating said signal, a time element device having a contactoperated from a normal to an operated position after a predeterminedtime interval of energization of such device, three alternate ,circuitpathsfor energizing said time element device one path of which includesa back contact of either of the two windings of said interlocking relayand a front contact of each of said two track relays, each of the othertwo circuit paths of which includes a full-released back contact of oneor the other winding of said interlocking relay and a front contact ofthe track relay associated with such full-released winding as well as aback contact of the other track relay, and means controlled by each ofsaid two track relays and by said contact of said time element devicefor establishing a pick-up circuit for the winding of said interlockingrelay associated with the one of said two track sections occupied by atrain in approaching the intersection, whereby to insure the operationof said signal for the time interval required by a car moving at anormal speed to traverse said intermediate section.

CHARLES W. BELLG

